In the gas supply section of semiconductor manufacturing equipment, a shutoff-opening device is used, and such a shutoff-opening device is obtained by assembling a plurality of on-off valves and one or more passage blocks (Patent Literature 1). FIG. 7 shows an example of the shutoff-opening device.
In FIG. 7, a shutoff-opening device 31 includes: a first on-off valve 32 disposed on a downstream side; a second on-off valve 33 adjacent to an upstream side of the first on-off valve 32; a third on-off valve 34 adjacent to an upstream side of the second on-off valve 33; a first passage block 35 having the shape of a rectangular parallelepiped and supporting the first on-off valve 32; a second passage block 36 having the shape of a rectangular parallelepiped and supporting the second on-off valve 33 and the third on-off valve 34; and a joint 37 provided on an end surface of a downstream side of the first passage block 35 and to be connected to an external device.
The first on-off valve 32 is a three-port diaphragm valve, the second on-off valve 33 is a two-port diaphragm valve, and the third on-off valve 34 is a two-port diaphragm valve.
The first passage block 35 corresponding to the first on-off valve 32 is provided with: a first on-off valve-corresponding first inflow passage 41; a first on-off valve-corresponding second inflow passage 42; and a first on-off valve-corresponding outflow passage 43.
The second passage block 36 corresponding to the second on-off valve 33 and the third on-off valve 34 is provided with: a second on-off valve-corresponding inflow passage 44; a second on-off valve-corresponding outflow passage 45; a third on-off valve-corresponding inflow passage 46; a third on-off valve-corresponding outflow passage 47; and a first on-off valve-corresponding communicating passage 48.
The second on-off valve-corresponding outflow passage 45 is in communication with the first on-off valve-corresponding second inflow passage 42 at a butt surface of the first passage block 35 and the second passage block 36 via a seal portion 49.
The first on-off valve-corresponding communicating passage 48 consists of: a first portion 48a having one end that is open to a rear surface thereof and having the other end that is in communication with a lower end portion of the third on-off valve-corresponding outflow passage 47; and a second portion 48b that is contiguous with the first portion 48a and extends forward. The second portion 48b is in communication with the first on-off valve-corresponding first inflow passage 41 at a butt surface of the first passage block 35 and the second passage block 36 via a seal portion 50.
The first on-off valve-corresponding second inflow passage 42 and the first on-off valve-corresponding outflow passage 43 that are passages leading to the first on-off valve 32, which is a three-port diaphragm valve, are normally in communication with each other via an annular groove 52a of a valve chamber 52.
In a state where the first on-off valve 32 is closed and the second on-off valve 33 is open, when a fluid is caused to flow into the second on-off valve-corresponding inflow passage 44 as shown by arrows in FIG. 7, the fluid flows through the second on-off valve-corresponding outflow passage 45 to the first on-off valve-corresponding second inflow passage 42 and then flows through the first on-off valve-corresponding outflow passage 43 to be supplied to the external device side.